THE HEART IS A HIGHLY SPECIALIZED BLOOD VESSEL WHICH PUMPS 72 TIMES PER MINUTE AND PROPELS AND 4,000 GALLONS OF BLOOD DAILY TO THE TISSUES

BLOOD

BLOOD IS COMPOSED OF CELLS AND A LIQUID INTERCELLULAR GROUND SUBSTANCE CALLED PLASMA. THE AVERAGE BLOOD VOLUME IS 5 OR 6 LITERS. PLASMA CONSTITUTES ABOUT 55% OF BLOOD VOLUME, CELLULAR ELEMENTS ABOUT 45%